The present invention relates to a magnetic tape storage medium for storing data, a write head module, a method for writing a servo pattern to a magnetic tape storage medium, a head module, and a method for reading a servo pattern from a magnetic tape storage medium.
A magnetic tape storage medium typically includes servo information prerecorded in one or more of dedicated servo bands that extend next to data tracks for storing data in a longitudinal direction along the tape storage medium. A servo band typically is read by a dedicated servo reader of a head module of a tape drive, into which a cartridge containing the tape storage medium is inserted to. The read servo information allows for determining a lateral deviation of the tape storage medium from a lateral reference position, which lateral reference position is desired for correctly reading data from and writing data to the tape storage medium by dedicated read and write elements of the head module. A position error signal supplied by the servo reader may be translated into a control signal for an actuator for controlling the lateral position of the head module with respect to the tape storage medium.
Timing-based servo (TBS) is a technology developed specifically for linear tape drives in the late '90s. In TBS systems, recorded servo patterns include transitions with at least two different azimuthal slopes. The head module lateral position is derived from the relative timing of pulses generated by a servo reader reading the servo pattern. TBS was adopted by the linear tape open (LTO) consortium, and a complete format for LTO tape drives of the first generation was standardized by the European Computer Manufacturers Association (ECMA) in 2001 as ECMA-319. The servo patterns in LTO are written on five dedicated servo bands that straddle four data bands.